Understanding the precursors, patterns and consequences of drug use and delinquent/ criminal behavior of high risk youths over time constitutes a key issue for field. Further, relatively little is known about the usefulness of testing juvenile detainees for drug use by urinalysis in identifying youths at risk of future drug use or delinquent/ criminal behavior. The research activities we propose will address these issues. Additional secondary analyses of a longitudinal data sit on a cohort of 399 juvenile detainees we have been collecting since December 1986 are planned; and further recidivism analyses will be completed. In particular, we plan to answer the following questions: (1) What is the role of family factors in the development of these youths' alcohol/other drug use and delinquent/criminal behavior over time? (2) What are the consequences of the youths' alcohol/other drug use? (3) Can a typology of the youths be developed, involving their sociodemographic-factors, alcohol/other drug use, mental health problems and referral histories at initial interview, which (a) distinguishes them and relates to future substance use, consequences of substance use and delinquency/crime? (4) What are the implications of our findings for a theory of the development of drug use among high risk youths? The project is expected to increase our understanding of the factors influencing high risk youths to pursue different developmental paths as they grow older; and to inform the design of prevention and intervention programs to address the needs of troubled youths entering the juvenile justice system, and their families.